Electrical sostenuto piano



Oct. 13, 1931. s. COOPER ELECTRICAL SOSTENUTO PIANO Original Filed March 25, 1927 lw i w w 627/? N UV Swweutoz Patented Oct. 13 1931 emwsmm fol-"P cs I smon coornn, or mommjm' Yonx announcer. sos'rmw'ro rmno Application filed March 25, 1927, Serial No. 178,207. Renewed March 14, 1931.

This invention relates to electrical sostee nuto operation of pianos. v,

One of the objects of hepresent invention is to provide a method of and apparatus for simpl' and satisfactorily overcoming a previous diflicultly, that of properly timing the energization of the string magnet with the movement of the string toward such magnet. The magnetic pluck, I have found,

should occur while the string is moving toward the magnet, while, on the other hand, the magnet should be at lowest ebb of energization during movement of the strin away from the magnet. Furthermore, have 16 found thatthe magneticpluck must occur often and with slight force, as distinguished,

from a rather infrequent pluck of considerable force; to avoid any derangement of'the nautral formationof theloo sand nodes 20 making the musical note. As state in my copending application Ser. No. 178,204, filed March 25, 1927, wherein the general principles underlying the present invention are described, and somewhat analogous invention structures are described and claimed, I have also found that'excellent results are obtained when the rapidly occurring current fluctuations through themagnet, each giving rise to a pluck on the string toward the magnet, and each occurring in timed relation to and as the result of a vibratile movement of the strin relative to a current pulsator or controller or themagnet,v occur at a frequency representing asub-multiple of the fundamental frequency of vibration of the string. 1 p p t The object foregoing, Iattain in the present case by the use of means giving special supportand connection for the pulsator relative to the vibrating musical string, and by incorporating 'instrumentalities for adjusting the pulsator relative to the support and if desired'for also or alternatively adjusting a connection part, the first mentioned ad'ustment being preferablyan adjustment 0 the pulsator angularly aroundthe string; as I have discovered that such adjustmentsv require comparatively little skill and time in order to set the pulsator to energize the magnet at the critical moment. i v I Another object is to provide an im roved type of pulsator of extremely simp e and compact type, of reliable operation, and ca-. pable when emplo ed with the new mount of 'coacting therewlth in a specially advantageousmanner inattaining the ob ect of the invention first stated. i

I Various otherobjects and advantages of the invention will be specifically pointed out or apparent hereinafter in the course of a description of a preferred one of the various possible forms of the invention as shown in the accompanying drawings; it being understood, of course, that such formis merely illustrative of one combination and arrangementof parts calculated to attain the objects of the invention, pursuant to-pi'esent prefer ence, and hence the detailed descri tion of such f ormnow to be given is not to e taken as at all defining or limiting the invention itself.

In the accompanying drawings:

Fi 1 is a diagrammatic view illustrating, toget er with one form of pulsator and circult, one form of mount according to the invention.

Fig. 2'is an enlarged view, showing, in full lines, the piano string andsaiddpulsator andlits mount in side elevation, an certain parts of the piano in vertical section.

. Fig. 3 shows, in full lines, the parts of Fig.2 in'top plan except as indicated by the section line 3 .3 of Fig. 2.

1Fig: 4 isan enlarged axial section of the pulsator of Fig. 2.

I Fig. '5 is a face view of a transverse element in saldpulsator of Fig. 2.

Fig. 6 is a View similar to Fig. 4, showing another form of pulsator.

Similar reference characters refer to similar parts throughout the several views of the drawings. o

In Fig. 1,one of the piano strings is indicated at 10, stretched over the bridge pieces 11 and 12. 13 indicates the electromagnet for vibrating the stringby magnetic pluck, and 14 the pulsator for controlling said magnet, said pulsator being located a circuit with the magnet, which circuit includes a suitable source of energy 15and a switch 16 operated by the piano key 17 when the latter is depressed.

The hammer for the string is conventionally indicated at H.

As shown most clearly in Figs. 2 and 3, wherein the upper bridge 11 and bearing-bar B appear more in detail but still somewl'nl conventionally, the pulsator may be positioned at about opposite the upper bridge, by means including a spring strip or rod member 26, desirably a comparatively heavy wire bent as shown, and suitably embedded or anchored at its end 26 in the piano body.

Comparing Figs. 2, 3, 4 and 5 with 6, it will be seen that the two forms of pulsator illustrated are of identical construction except that the element 28, which is of some non-resonant material as felt or M 001, is

omitted as a spacing element between electrode 18 and the preferably more massive companion electrode 19. Except for the dif ference just noted, each pulsator shown includes these two electrodes, acommon sheath orenvelope 25 holding both electrodes, which sheath is also of n0n-resonant material as felt or wool, and a mass or collection C of conducting material in fragmentary condition between the opposed facesof the electrodes. The sheath or envelope 25' in the present case acts not only as a non-resonant mount for the more massive electrode, but also as a carrier for both electrodes and the contents of the chamber 27 formed between their opposed faces. In order to more securely bind the parts together, and yet keep undisturbed the generally non-vibratile mount desirable for the two electrodes, the pulsator may be bound loosely, as indicated, by a strand or strands of wool yarn 25w or the like.

To attain the advantages described and claimed in my copending application above identified, of having self-renewing contact faces, the collection C is loose within chamber 27, whether or not the spacing element 28 is in said chamber, as indicated at 27' in Figs. t and 6. hen said spacing element is preseat the collection C is broken up into groups and these groups are loose sub-collections of fragmentary conducting material in each of the pockets marked oil in said chamber by the through openings in said element 28 as indicated at 28a in Fig. 5. Referring to the form of Fig. 6, it will be understood that here the collection of conducting material acts solely as the spacing element for the electrodes; such collection being capable of so acting even when loose in the chamber 27, as will be understood.

The new mount for the pulsator' includes as above the spring rod or wire member 26. Such member has'preferabl'y a double or reversed rather deep intermediate goose-neck portion as shown, and presents an upwardly extending terminal length beyond and some distance awa from the piano strings. The lectrode 18 o the pulsator has screwed therein a threaded stud 29, this stud carrying a pair of nuts which may be screwed up tight to mount the electrode 18 and hence the whole pulsator on said terminal length of the bent wire member 20'. One of these nuts, as clear- 1y indicated in Fig. 2, my have a straight halt-round groove cut in its end facing the strand isfastened at one end tothe string near or about its bridge support 11a, and at the other end to the bent rod member 26 not far from the securing nuts for the pnlsator.

In operation, when the string 10 vibrates, it transmits motion to the long terminal upstanding end of the member 26, and thence to the electrode 18.-

Since electrode 19' is suspended: in an enrelope which has little resonance and relatively slight recoverance, it is to a great 'i extent subieet to the inertia of itsmass bus, when the electrode 1.8 is put into rapid osciI- latory motion, the electrode 19 is comparat-ively lethargic in. its movement, and so the carbon granules between the two electrodes are caused to vary in electric conductivity, slightly, yet very rapidly, and with a rate 055 current fluctuation rather elosethan other 'wise to the rate of vibration of the string; all asexpla'ined fully and claimed, in my 00- pending application above identified.

The presence of themember 26 or an equivalent, however, rather intensifies this rapidity oicurrent fluctuation, while failing to act, in spite oi its own natural period of vibration, deleteriouslyin regard tothe true sostennto desired, and While permitting other adjustments in aid of such sostenuto. When thenatural pitch of vibration acts distortingly' on the sostenuto, the phase or amproperly timed with thatof the string 10, the point of'connection of the strand 30- on the: string itself may be varied. I have found that boththese troubles may be overcome in most casesby maintaining the point of connection between the strand and the string, and thus solely by changing the point of connection between the strand and the member 26; particularl whenthe pulsator angularly adjusted a ut the upstanding terminal length of saidmember, which is an especiallyeasy adjustment 'toimake. Often, 7

this *pulsator adjustment alone results 1 in uick co ordination of the variouselements or true sostenuto. Y ,7 In practice, it is sometimes jparticularly difficult to insure that the pulsator willvibrate with the same frequency as the hightension musical strings inthe treble; butI turba'ncein the'natural formation ofthe mu-' sical string, and the result is a sweet, mellow musical note sustained as long as desired, in other words, true sostenuto.

I have found that when the pulsator has 5; been adjusted for one particular note of the piano, this adjustment may serve for control of the adjoining notes on both sides; and it is only necessary to make the pro er circuit connections to the magnets for t ese notes,

say by placing'the latter'magnets in parallel in a common circuit with thepulsator, and to connect, as shown at 31 and 32 in Fig. 3, other strands to the pulsator, and in this t way have the one pulsator control two, or

more notes of the piano, themagnets for such other stringsbeing in circuit with their respective switches 16 and connected in multiple with battery 15.

Inasmuch as many changes could be made in the above constructions,- andmany apparently widely different embodiments of my invention could be made without departing I from the scope thereof, it is intended that all matter contained inthe above description or shown in the accompanying drawings shall be interpreted as illustrative'and not in a limiting sense.

It is also to beunderstood that the language contained in the following, claims is intended to cover all the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language,might be said to fall therebetween. I i i What I claim is:

1. In a device of the kind described, a vibratile string, a resilient support mounted to vibrate in sympathy with the string, a pulsator, means for coupling the pulsator to the string for vibration therewith and including said support, a magnet in circuit with the pulsator and adapted to actuate the string, and an auxiliary means for coupling the pulsator to the string for vibration therewith including a mechanical constring, and an aux ilia'ry lneans for coupling nectiofi between-the pulsator and its support, and'the string; i '2. In'a device of the kind described, a vibratile string, a resilient support mounted to vibratein' sympathy with the string, a pulsator, means for coupling the'pulsator to the string for vibration therewith a-nd'in-n cluding said support, a magnet in circuit with the pulsator and adapted to actuate the the pulsator to the string for vibration therewith including a direct mechanical connection between-said support and the string.

3; In a device of the" kind described, a vibratile string, a resilient support mounted tovibrate in sympathy" with the string, a

vpulsator,,me'ans for coupling the pulsator to the string for vibration therewith and including said'support, a magnet in circuit with the 'pulsator "and adapted to actuate the 8 string, and an'auxiliary means forcoupling the pulsator to the string for vibration there-- with including a direct mechanical connection between said support and the string, said connection being a wire'kept taut by tension. 4. In a device of the kind described, a vibratile string, a resilient support mounted to vibrate-with the string,'a pulsator bodily carried by said support at a distance from the string, said pulsator including a plurality 9 of spaced and relatively movable electrodes, and means for varying the action of said electrodes b angularly adjusting the pulsator on saidysupport.

5.111 a device "of the kind described, a

6. In a device of the kind described, a

vibratile string, aresilient-support mounted to vibrate with the string, a pulsator bodily carried'by said support at a distance from the string, said pulsatorincluding a plurality of spaced and relatively movable electrodes, and means for varying the action of said electrodes by rotating the pulsator in a substantially horizontal plane.

f7. Ina device of; the kind described, a vibratile string, a resilient support mounted to vibrate with the string, a pulsator bodily carried by said sup ort at a distance from thestring, said pu ator including a plurality of-spaced and relatively movable electrodes, and means-for varying 'theaction of said'electrodes byrocking the, pulsator about a point spaced from the string.

8. In a device of the kind described, a vibratile string, a, resilient supportmounted to vibrate with the string, a pulsator bodily Q0 electrodes by changing the angular relation of the space between said electrodes and the plane of vibration of the string. V

9'. In a device of the kind described, a vibratile string, a resilient support mounted to vibrate with the string, a pulsator on said support, and means for coinciding the action of the magnet and the vibration of the string, said means including a means for varying the positon of thepulsator on the support, and amechanical connection between the pulsator and its support, and the string, said connection being adjustable along the length of the string.-

10. In a device of the kind described, a

vibratile string, a resilient support mounted to vibrate with the string, a pulsator on said support, and means for coinciding the action of the magnet and the vibration of the string, said means including a means for varying the position of the pulsator on the support,

and a mechanical connection between the pulsator and its support, and the string, the support having an elongate vibratile portion spaced from the string and said connection being adjustable along the length of said portion.

11. The device defined in claim 8, wherein said connection is also ad'ustable as to its end nearer the pulsator an support.

12. In a device of the kind described, the combination of avibratile string, a pu'lsator, means including a vibratile support itself supported on a part other than the string but for vibrating the pulsator with the string, and means associated with the string for preventing distortion from the inherent pitch of vibration of the first-mentioned means.

13. In a device of the kind described, the combination of a vibratile string, a pulsetor, means including a vibratile support, a flexible connection between the support and the string for vibrating the pulsator with the string, and means associated with said support for preventing distortion from the inherent pitch of vibration of said support.

14. In a device of the kind described, the combination of a vibratile string, a pulsator, means including a vibratile support for vibrating the pulsator with the string, and means for preventing sostenuto distortion from the inherent pitch of vibration of a component of the first-mentioned means, the distortion preventing means including an inst'rumentality for adjusting the pulsator relative to the first-mentioned means, said support being mounted non-contactingly of the string.

15. In a device of the kind described, the combination of a vibratile string, a pulsafor, means including a vibratile support for vibrating the pulsetor with the string, and means for preventing sostenuto distortion from the inherent pitch of vibration of a component of the first-mentioned means, the distortion preventing means includin an instrumentelity for permitting a variable mechanical connection between the first-mentioned means and the pulsator, and the string.

16. In a device of the kind described, a vibratile string, a resilient member support ed out of contact with the string but to vibratein sympathy therewith, a pulsator bodily carried by said resilient member, and a magnet in circuit with the pulsator for operating the string for sostenuto.

17. In a device of the kind described, a vibratile string, a resilient member supported out of contact with the string but to vibrate in sympathy therewith, a pulsator bodily carried by said resilient member, a magnet in circuit with the pulsator for operating the string for sostenuto, andmeans for timing the energization of the magnet to pluck the string during movements of the latter toward the magnet and for otherwise insuring substantially undistorted sostenuto,

18. In a device of the kind described, a. vibratile string, a resilient member supported out of contact with the string but to vibrate in sympathy therewith, a pulsator bodily carried by said resilient member, a magnet in circuit with the pulsator for operating the string for sostenuto, and means for insuring that the rate of vibration of the pulsator will be a sub-multiple of the rate of vibration of the string.

19. In a device of the kind described, vibratile strings of two difierent notes, a magnet assocated with each string, a pulsator for actuating both magnets, and a mount for the pulsator including a supporting member secured to a part of the piano other than a string thereof and also including a separate mechanical connection from said mount to each of the two strings.

20. In a device of the kind described, vibratile strings of two different notes, a magnet associated with each string, a pulsator for actuating both magnets, and a mount for the pulsator including a supporting member secured to a part of the piano other than a string thereof and also including a separate strand of wire from said mount to each of the two strings.

21. In a device of the kind described, vibratile strings of two difierent notes, a magnot associated with each string, a pulsator for actuating both magnets, and a mount for the pulsator including a supporting member and a separate, mechanical connection from said mount to each of the two strings, said member being resilient and said connections ibeing; strands more flexible than said mem- 22. In electrical sostenuto for pianos, the method of utilizing a pulsator operated by the vibration of a string and a magnet energized by such pulsator to sustain the vibration of the string, whichinvolves imparting vibrations to the pulsator from the string through a path including a part of the piano other than the string and simultaneously imparting vibrations to the pulsator through a path exclusive of said piano part.

23. The method defined in claim 21, wherein the pulsator vibrations are further modified in aid of true sostenutoby modifying the relation of one of said paths to the line of extension of the string.

24. The method defined in claim 21, wherein the pulsator vibrations are further modi fied in aid of true sostenuto by'modifying I the relation of one of said paths angularly relative to the plane of vibration of the string.

25. The method defined in claim 21, wherein the pulsator vibrations are further modified in aid of true sostenuto by modifying the relation of oneof said paths to the line of extension of the string, and by modifying a line of extension ofone of said paths in a plane substantially perpendicular to the line of extension of the strin In testimony whereof aflix m si%1ature.

SIMON C 60 ER. 

